MICROANATOMY

Detailed explanation-1: -Inspiration (inhalation) is the process of taking air into the lungs. It is the active phase of ventilation because it is the result of muscle contraction. During inspiration, the diaphragm contracts and the thoracic cavity increases in volume.

Detailed explanation-2: -When the lungs inhale, the diaphragm contracts and pulls downward. At the same time, the muscles between the ribs contract and pull upward. This increases the size of the thoracic cavity and decreases the pressure inside. As a result, air rushes in and fills the lungs.

Detailed explanation-3: -Active inspiration involves the contraction of the accessory muscles of breathing (in addition to those of quiet inspiration, the diaphragm and external intercostals). All of these muscles act to increase the volume of the thoracic cavity: Scalenes – elevates the upper ribs. Sternocleidomastoid – elevates the sternum.

Detailed explanation-4: -Inspiration allows air to flow into the lungs. The second phase is expiration. Expiration involves gases leaving the lungs. During inspiration, the diaphragm and intercostal muscles contract allowing air to enter the lungs.

Detailed explanation-5: -INSPIRATION. Breathing in is called inspiration. It is an active process. The major muscles in quiet inspiration are the diaphragm and the external intercostals.